code: def test_transform_observation_features(self) -> None:
      # Verify running the transform on already-casted features does nothing
      observation_features = [
          ObservationFeatures(
              parameters={"a": 1.2345, "b": 2.34, "c": "a", "d": 2}
          )
      ]
      obs_ft2 = deepcopy(observation_features)
      obs_ft2 = self.t.transform_observation_features(obs_ft2)
      self.assertEqual(obs_ft2, observation_features)
      obs_ft2 = self.t.untransform_observation_features(obs_ft2)
      self.assertEqual(obs_ft2, observation_features)
  
file_path: Ax/ax/modelbridge/transforms/tests/test_cast_transform.py
imports: from copy import deepcopy
  from unittest.mock import patch
  from ax.core.observation import ObservationFeatures
  from ax.core.parameter import ChoiceParameter, FixedParameter, ParameterType, RangeParameter
  from ax.core.search_space import HierarchicalSearchSpace, SearchSpace
  from ax.modelbridge.transforms.cast import Cast
  from ax.utils.common.constants import Keys
  from ax.utils.common.testutils import TestCase
  from ax.utils.testing.core_stubs import get_hierarchical_search_space
label_desc: Use image node_id 2 for calling the CastTransformTest obj's underlying member method code with example usage: obj.test_transform_observation_features() without return types